1. Field of the Invention
This invention relates generally to a water closet of the type having a tank for storing water at a level whereat a substantial volume of the water will not gravity flow into the bowl rim, and more particularly to an arrangement including a tank water withdrawing means for causing tank water to be utilized during flushing to supplement flow to the bowl rim from the main water supply.
2. Description of the Prior Art
The most common type of water closet in use comprises a bowl and a flush water tank mounted above the bowl. Upon flushing, all of the flush water in the tank will flow by gravity into the bowl. Usually the bowl and tank are in separate pieces and thus this type is frequently termed a two-piece water closet. The bowl has an upper rim containing a water passage having a plurality of holes or jets through which water can flow. During flushing, all or substantially all of the flush water from the tank enters the bowl through rim jets to wash the bowl sides and this action is generally termed "rim wash". Two of the primary functions that a modern water closet should provide is water conservation in order to reduce the volume of water usage and an efficient rim wash for sanitation purposes. In order for a water closet to be classified as "water-saving" under United States standards (ANSI A112.19.2M-1982) or "conservation-type" under Canadian standards (Can/CSA-B45-Series-88) it is required that the water closet use no more than an average of 3.5 gallons (13.5 liters) per flushing cycle with a water supply pressure in the range of 20 to 80 psi. With regard to rim wash, the ANSI standards provide that "an artist's fine point, felt-tipped pen containing a dark-colored, water soluble ink" be used to "ink a line around the circumference of the flushing surface at a level 1 in. (25 mm) below the rim jets of the bowl." To meet the rim wash performance requirement, "the total length of ink line segments remaining on the flushing surface after each initial flush shall not exceed 2 in. (50 mm) and no individual segment shall be longer than 1/2 in. (13 mm) based on average of the three test runs."
Two-piece water closets can easily meet the above standards which define the volume of water that can be used by a water-saving closet and the amount of rim wash required to meet sanitary and water-saving requirements because the tank is above the bowl and all, or substantially all, of the flush water can be directed to enter the bowl through the rim jets.
While a two-piece water closet operates quite satisfactorily, it does have two shortcomings: first, the two-piece water closet has an unreasonably high noise level during flushing and, second, from an aesthetic standpoint the high tank does not permit the water closet to have a low, designer-type profile that is now popular. The desire to reduce flushing noise and provide a low profile resulted in the development of a second type of water closet with the tank at substantially the same level as the bowl, and thus while such a water closet has low noise when flushing and a low profile, there is little or no head of water available to flow under the force of gravity into the rim jets to provide the required rim wash. This second type is generally called a low profile, one-piece water closet as the tank and bowl are usually molded in one piece even though the tank could be a separate component. In the one-piece water closet, the flush water is also introduced via the rim and an opening in the bowl adjacent a bottom portion thereof, but as there is virtually no gravity flow of flush water into the bowl rim, the rim wash of the sides of the bowl tends to be inadequate especially when the water supply pressure is low.
The prior art solution to the problem of providing an adequate flow of water into the rim for rim wash in a one-piece water closet is to install a diverting arrangement to divert the pressurized water from the water supply inlet directly to the rim during the first part of the flush cycle to provide the rim wash. This direct supply of water is then turned off when the rim wash is complete. This is an acceptable arrangement when the flow through the water inlet is at a pressure and volume sufficient to provide the required rim wash as detailed above and the water closet does not have to be rated as "water-saving". U.S. Pat. No. 4,408,361, issued Oct. 11, 1983 to Roy J. Rozck, discloses a typical prior art diverting arrangement. It is desired to provide a proper rim wash even with water supplied at a pressure as low as 20 psi with total water consumption per flush cycle not exceeding 3.5 gallons in order to achieve a water-saving rating. In many areas, water closets cannot be legally installed if they do not have a water saving rating. While the present one-piece water closet diverter arrangements do provide a flow of water to the rim, the volume of such flow is either not sufficient to meet the above discussed plumbing standards for rim wash at the low end of the pressure range, i.e., 20-25 psi or if it is sufficient, then the total volume used per flush is too high to permit the one-piece closet to be classified as a water-saving or conservation type.
Therefore, a need exists for providing a water closet, of the type wherein all of the flush water in the tank is at a level where it will not flow by gravity into the rim, with an arrangement that will meet plumbing standards regarding both rim wash and water conservation at all times even when the water supply pressure is at the low end of the range.